The invention relates to a method and a device for fixing the end of the fiber sliver on fiber sliver cans by means of a clamping device, whereby the end of the fiber sliver on the fiber sliver can hangs down loosely on the outer surface of the can and the can is able to rotate on its longitudinal axis.
With the operation of textile machines, e.g. spinning machines, fiber sliver cans are continually filled and emptied. Thereby, the empty fiber sliver cans are changed for full cans and vice versa. With every delivery of a full fiber can in the working process of the fiber sliver, the end of the fiber sliver must be caught and guided into the textile machine.
German Patent Specification DE 26 46 313 discloses a device by means of which a textile sliver hanging over the rim of a can is fed into a fiber sliver feeding device of a spinning machine. This device comprises a swivel arm with a clamp with which the end of the fiber sliver is held. As, with this device, the swivel arm is fixed rigidly to a can changing device and the can, for its part, is positioned permanently in a manipulator, then the fiber sliver must hang down in a place over the rim of the can which is determined exactly and/or be laid in the swivel arm manually and firmly clamped there. This operation is labor-intensive and prevents the desired automatic progress of the spinning operation.
Another device and a method for fixing a fiber sliver and which hangs on the outside of containers is disclosed in the European Patent Specification No. 69 087 B1. Here, the containers, fiber sliver cans, for instance, are pushed along a transport route between various textile machines. In addition to the transport route, a catcher device is arranged for the sliver ends, which can be slid along a partial area of the transport route. The catcher device has sensors, by means of which the presence of a sliver in the area of the catcher device may be determined. For fixing the sliver end, firstly, a can is brought into the vicinity of the catcher device and then the can is rotated on its longitudinal axis until a sensor of the catcher device, arranged against the outer surface of the container detects the sliver. Subsequently, the catcher device must be brought up to the outer surface approximately at right angles to the container. In addition, the container and the catcher device must be pushed in the vertical direction relatively to each other, in order to bring the end of the sliver into the correct catching position. The detection of the sliver by means of the sensor is already beset with difficulties. The sliver is often hanging in a position which is inclined, twisted, kinked or irregular in some other way on the outer surface of the container. Or, longitudinal seams or other disturbing elements are present on the container surface, which the sensor erroneously detects as textile slivers. In the latter case, the sliver end cannot be fixed and the can or the entire process is stopped. With inclined or kinked slivers the sensor can, indeed, detect a sliver, but it loses it again through the vertical process, or the clamping elements do not close on the sliver, as they are incorrectly conveyed. Through this, disturbances appear and the automatic operation of the process must be frequently interrupted. It is also possible, that the end of a sliver, which is situated too far from the container outer surface is entangled on the outside of the catcher device or of the clamping elements and cannot be caught at all. Furthermore, the positioning of the catcher device in several steps wastes time and requires more drives and control elements, whereby the susceptibility to disturbances of the installation is likewise increased. This known method is not able to satisfy the requirements of an automatic operation sequence.